iphone - 如何设置最小时间每次都显示为UIDatepicker中的默认时间

Question

在Datepicker中，我已经设置了uidatepicker可以滚动的最小和最大时间，例如，我将3:00 PM设置为最小时间，将8:00 PM设置为最大时间，当我运行该应用程序时，我希望日期选择器显示最小时间而不是当前时间设备的。我在xib文件中没有使用的项目中对UIDatepicker进行了硬编码。我已经设置了最小时间，但是当我从control.tag == 1切换到2时，最小时间会发生变化，而且当我第一次打开应用程序时，日期选择器不会从最小时间开始。

更新:

-(IBAction)notificationButtonChanged:(UIButton *)control
{

    if (control.tag == 1)
    {
        self.selectedButton = control.tag;

        [userTimePicker reloadInputViews];

        [components setHour:7];;
        [components setMinute:00];

        NSDate *date1 = [gregorian dateFromComponents:components];

        [components setHour:11];
        [components setMinute:00];

        NSDate *date2 = [gregorian dateFromComponents:components];

        [userTimePicker setDatePickerMode:UIDatePickerModeTime];

        [userTimePicker setMinimumDate:date1];
        [userTimePicker setMaximumDate:date2];

    }

    if (control.tag == 2)
    {
        self.selectedButton = control.tag;

        [userTimePicker reloadInputViews];

        [components setHour:12];
        [components setMinute:00];

        NSDate *date1 = [gregorian dateFromComponents:components];

        [components setHour:17];
        [components setMinute:00];

        NSDate *date2 = [gregorian dateFromComponents:components];

        [userTimePicker setDatePickerMode:UIDatePickerModeTime];

        [userTimePicker setMinimumDate:date1];
        [userTimePicker setMaximumDate:date2];

    }

}

Answer 1

编辑:

int startHour = 7;
int endHour = 11;

NSDate *date1 = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier: NSGregorianCalendar];
NSDateComponents *components = [gregorian components: NSUIntegerMax fromDate: date1];
[components setHour: startHour];
[components setMinute: 0];
[components setSecond: 0];
NSDate *startDate = [gregorian dateFromComponents: components];

[components setHour: endHour];
[components setMinute: 0];
[components setSecond: 0];
NSDate *endDate = [gregorian dateFromComponents: components];

[userTimePicker setDatePickerMode:UIDatePickerModeTime];
[userTimePicker setMinimumDate:startDate];
[userTimePicker setMaximumDate:endDate];
[userTimePicker setDate:startDate animated:YES];
[userTimePicker reloadInputViews];